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Show children with different text than the filter

How to

Filter nodes so that a search by a custom text can return nodes whose text does not contain it.

By default, the filtering of the RadDropDownTree works with the text of the node, so if the string the user entered is not present in the Text of the node, the node will not be returned.

Solution

If you want the node to come up in searches for other strings, you need to

  • have that text rendered in the node template

  • set the FilterTemplate to ByContent

Note that this increases the footprint of the nodes on the page and with large content or number of nodes it may cause a performance hit.

Here is a basic example:

<telerik:RadDropDownTree runat="server" ID="RadDropDownTree1" EnableFiltering="true" OnNodeDataBound="RadDropDownTree1_NodeDataBound">
    <FilterSettings FilterTemplate="ByContent" Filter="Contains" />
    <DropDownNodeTemplate>
        <div class="nodeTemplate">
            <span>
                <%# DataBinder.Eval(Container, "Text") %>
            </span>
            <asp:Label Text="" ID="hiddenContent" CssClass="hiddenContent" runat="server" />
        </div>
    </DropDownNodeTemplate>
</telerik:RadDropDownTree>
<style>
    .hiddenContent {
        display: none;
    }
</style> 
and some sample server-side code to run this:
    protected void RadDropDownTree1_NodeDataBound(object sender, DropDownTreeNodeDataBoundEventArguments e)
    {
        if (e.DropDownTreeNode.Value == "Peacock") //simulate some logic for adding hidden search text
        {
            (e.DropDownTreeNode.FindControl("hiddenContent") as Label).Text = "custom string";
        }
    }

    //sample data binding follows
    protected void Page_Init(object sender, EventArgs e)
    {
        RadDropDownTree1.DataFieldID = "ID";
        RadDropDownTree1.DataFieldParentID = "ParentID";
        RadDropDownTree1.DataValueField = "Value";
        RadDropDownTree1.DataTextField = "Text";
        RadDropDownTree1.DataSource = GetDDTData();
        RadDropDownTree1.DataBind();
    }

    public DataTable GetDDTData()
    {
        DataTable table = new DataTable();
        table.Columns.Add("ID");
        table.Columns.Add("ParentID");
        table.Columns.Add("Value");
        table.Columns.Add("Text");

        table.Rows.Add(new String[] { "1", null, "Markering", "Marketing" });
        table.Rows.Add(new String[] { "2", null, "Sales", "Sales " });

        table.Rows.Add(new String[] { "3", "1", "Callahan", "Laura Callahan" });
        table.Rows.Add(new String[] { "4", "1", "Dodsworth", "Anne Dodsworth" });
        table.Rows.Add(new String[] { "5", "1", "King", "Robert King" });
        table.Rows.Add(new String[] { "6", "1", "Suyama", "Michael Suyama" });
        table.Rows.Add(new String[] { "7", "1", "Buchanan", "Steven Buchanan" });
        table.Rows.Add(new String[] { "8", "1", "Peacock", "Margaret Peacock" });

        table.Rows.Add(new String[] { "9", "2", "Leverling", "Janet Leverling" });
        table.Rows.Add(new String[] { "10", "2", "Davolio", "Nancy Davolio" });
        table.Rows.Add(new String[] { "11", "2", "Fuller", "Andrew Fuller" });
        table.Rows.Add(new String[] { "12", "2", "Johansson", "Mark Johansson" });


        return table;
    }
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